Impact of Radiotherapy on Radiation-Induced Brain Injury in Patients with Nasopharyngeal Carcinoma Using Nano-Magnetic Resonance Imaging

Abstract

This study investigate the changes of white matter injury induced by radiation after radiotherapy in patients with nasopharyngeal carcinoma (NPC) and its association with cognitive dysfunction using multiple MRI methods. A total of 42 patients with NPC who underwent radiotherapy at xxx Hospital between December 2018 and June 2021 were included. The patients were randomly divided into 4 groups based on the timing of radiotherapy. Superparamagnetic iron oxide nanoparticles were used as MRI contrast agents. DTI and MRS scans were conducted to measure FA, ADC, NAA/Cho, Cho/Cr, and NAA/Cr ratios in the hippocampus of both temporal lobes. A cognitive assessment was performed using the MoCA and MMSE scales. After radiotherapy, patients experienced a decline in cognitive scores, which stabilized after 6 months. White matter changes were observed in the hippocampus, with decreased FA and increased ADC values that gradually returned to normal levels. Cho value increased and NAA value decreased initially but eventually returned to pre-treatment levels. No significant changes occurred in the Cr value. Metabolite ratios decreased within 3 months post-radiotherapy but gradually increased thereafter, remaining lower than pre-treatment levels at 6 months. Higher radiation doses did not significantly affect FA and ADC values but decreased white matter metabolite ratios. In conclusion, we reveal that the dosage and duration of radiotherapy can influence the degree of brain injury in patients with NPC and highlights the cognitive decline, white matter changes, and changes in metabolite ratios after radiotherapy for NPC, providing insights into the effects of radiation on brain structure and function.